10Having access to accurate travel time is of great importance for both highway network users and 11 traffic engineers. The travel time which is currently reported on several highways is estimated by 12 employing naïve methods and using limited sources of data. This results in unreliable and 13 inaccurate travel time prediction and could impose delay on travelers. Therefore, the main 14 objective of this study is short-term prediction of travel time for highways using multiple data 15 sources including loop detectors, probe vehicles, weather condition, network, accidents, road 16 works, and special events in order to consider the effect of different factors on travel time. To this 17 end, two machine learning methods, K-Nearest Neighbors and Random Forest, are employed. 18 After applying data cleaning process on datasets and combining them, the models are trained to 19 predict and compare short-term harmonic average speed as a representative of travel time for 5-20 minute prediction horizons in one hour ahead. The travel time is calculated as the ratio of the length 21 of each link and the harmonic average speed for all reporting vehicles. Hence, a model is trained 22 for each technique to predict travel time 5 minutes ahead, 10 minutes ahead, and all the way down 23 to 60 minutes ahead. The results confirm satisfying performance of both models in short-term 24 travel time prediction with slightly outperformance of Random Forest model. A feature importance 25 and sensitivity analysis also applied for the Random Forest model, and traffic variables are found 26 as the most effective variables in predicting the travel time. 27 28